1. Field of the Invention
The present invention relates to an optical sheet and a display device having the same. More particularly, the present invention relates to an optical sheet improving light-condensing efficiency and a display device having the optical sheet.
2. Description of the Related Art
In a liquid crystal display (“LCD”) display device, an optical sheet is used for improving the optical characteristic, such as brightness and front brightness, of light provided to a display panel. The optical sheet may include a film, such as a polyester sheet having adhesive property used as a base film, and ultraviolet curable resin laminated on the base film.
The optical sheet may include a prism sheet improving front brightness by converging the advance direction of light into a perpendicular direction to a display panel. A prism sheet such as is shown in FIG. 10 of the U.S. Pat. No. 5,600,455 includes prisms having a triangle shape in the cross-section view and extended to one direction. The prism sheet condenses incident light on plane perpendicular to the direction of prisms, into the perpendicular direction of the prism sheet, but cannot condense incident light on plane parallel into the direction of prisms.
Two prism sheets may be disposed in perpendicular to each other are used for condensing light into vertical and horizontal directions. However, the prisms mentioned above have technical difficulties for the price and the weight.